1. Field of the Invention
This invention relates to a disc drive suspension used in an information processor, such as a personal computer.
2. Description of the Related Art
A hard disc drive (HDD) used in an information processor, such as a personal computer, comprises a carriage that can turn around an axis. The carriage is turned around the axis by a positioning motor. The carriage comprises an actuator arm, a suspension (disc drive suspension) provided on the distal end portion of the arm, a head portion including a slider mounted on the suspension, and the like. When the disc rotates, the slider slightly floats above a surface of the disc, and an air bearing is formed between the disc and the slider. This suspension is composed of a base portion including a base plate, a load beam formed of a precision thin plate spring, and a flexure fixed to the load beam by laser spot welding or the like.
For the disc drive suspension constructed in this manner, the seek time is expected to be shortened to cope with higher-density data to be recorded in discs and higher-speed disc rotation. The suspension should be reduced in weight to shorten the seek time. In order to enhance the impact resistance of the suspension, moreover, it is desirable to make the load beam and the like lighter in weight. Means for reducing the weight of the load beam is proposed and described in Jpn. Pat. Appln. KOKAI Publication No. 2002-133805. According to this means, the thickness of the load beam is reduced by partial etching.
The thickness of a region (partially etched portion) that is thinned by partial etching is about half the material thickness of the load beam. If a load beam that is formed of a stainless-steel plate of, e.g., 60-μm thickness is partially etched, the thickness of the partially etched portion is about 30 μm. Inevitably, moreover, the thickness of the partially etched portion varies in some measure.
If the thin partially etched portion is subjected to laser spot welding, a laser beam sometimes may penetrate a laser weld, thereby lowering the appearance quality of the suspension or damaging a welding jig. If the output of a laser oscillator is lowered, the welding strength may possibly be reduced, although the laser weld can avoid being penetrated by the laser beam.